The present invention relates to capacitive touch pads and more particularly to novel touch pad construction enabling the pleasing appearance of light-colored touch pads for an appliance control panel.
Use of glass capacitive touch control panels for appliance controls is well known. However, such control panels typically employ touch pads which are relatively dark in color. Current trends in kitchen design have created a need for a glass capacitance touch control panel with white touch pads with black lettering and/or symbols. The control panel touch pads must meet the normal standards for such panels, namely that the pad must be conductive, must be of at least a minimum size, and must be resistant to abrasion and to corrosive food stuffs. Such pads are normally applied by screen printing a ceramic enamel to which a metallic powder has been added. The printed film is then fired to form a conductive glassy film. The conventional approach provides satisfactory results for relatively dark-colored pads. However, the necessary addition of commonly used conductive metallic components to a white enamel darkens the enamel resulting in an off-white or gray color. Use of almost pure silver as the metallic component results in a reasonably satisfactory white color; however, it lacks other required properties and is subject to tarnishing on exposure to the air.
In view of the aforementioned shortcomings of the prior art, a need exists for a means of providing capacitive touch control panel having white touch pads.